The selling comes after a gunman opened fire (http://www.marketwatch.com/story/reports-of-dead-injured-after-mass-shooting-at-las-vegas-concert-2017-10-02) on a crowd at an outdoor country-music concert in Las Vegas on Sunday night, leaving at least 50 people dead and more than 400 injured.

The shots came from the 32nd floor of MGM's Mandalay Bay Resort and Casino on the Vegas Strip, said multiple media reports citing authorities. Police said the suspected shooter is dead after firing on the concert grounds below.

"Our thoughts & prayers are with the victims of last night's tragic events," MGM Resorts said in a tweet. "We're grateful for the immediate actions of our first responders."